Effects of copper on growth and on photosynthesis of mature and expanding leaves in cucumber plants
Effects of copper on growth and on photosynthesis of mature and expanding leaves in cucumber plants
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DOI：
10.1016/s0168-9452(02)00060-2
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发表时间：
2002-07
期刊：
影响因子：
5.2
通讯作者：
Florence Vinit-Dunand;D. Epron;B. Alaoui-Sossé;P. Badot
中科院分区：
文献类型：
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作者：
Florence Vinit-Dunand;D. Epron;B. Alaoui-Sossé;P. Badot
本研究的目的是研究铜处理黄瓜幼苗生长抑制与光合作用之间的关系。播种后22天，将铜添加到营养液中5天，导致沙子中的最终铜补充浓度分别为0（对照）和10μg g−1（铜胁迫）。黄瓜叶片对铜添加的反应取决于其生长阶段。幼嫩展开的叶子表现出叶面积减少，而成熟叶子表现出光合作用显着下降。两种叶子中的蔗糖和淀粉含量均有所上升。对于成熟叶片，净CO2同化在细胞间CO2摩尔分数几乎恒定的情况下下降，表明气孔关闭并不能解释光合作用的抑制。暗适应叶片中 PSII 的最大光化学产量不受影响，表明光合作用的暗期而不是亮期受到影响。胁迫植物的相对生长速率和叶面积比显着低于对照植物，而铜胁迫植物的净同化率没有明显下降。因此，尽管成熟叶光合作用减少，但生长减少更有可能是由于整个植物叶面积的减少。光合作用的下降可能是源库关系改变的结果，而不是由于铜对光合作用的毒性作用。
The aim of this study was to study the relationship between growth inhibition in Cu-treated Cucumis sativus L. seedlings and photosynthesis. Twenty-two days after sowing, copper was added to the nutrient solution for 5 days, leading to final Cu supplementary concentration in sand of, respectively 0 (control) and 10 μg g−1(Cu stress). The responses of cucumber leaves to copper addition depend on their growth stage. Young expanding leaves showed a reduction in leaf area, while mature leaves exhibited a significant decline in photosynthesis. Sucrose and starch content rose in both types of leaves. For mature leaf, net CO2assimilation declined at a nearly constant intercellular CO2mole fraction, indicating that stomatal closure did not account for the inhibition of photosynthesis. Maximal photochemical yield of PSII in dark-acclimated leaves was unaffected, indicating that the dark phase of photosynthesis rather than the light phase was affected. Relative growth rate and leaf area ratio of stressed plants were significantly below that of control plants while no significant decrease of net assimilation rate was observed for Cu-stressed plants. Thus despite a reduction in mature leaf photosynthesis, growth reduction is more likely due to a reduction in whole plant leaf area. This decline in photosynthesis is probably a consequence of an altered source–sink relationship, rather than due to a toxic effect of copper on photosynthesis.